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한국센서학회> 센서학회지> Suppression of Dielectric Loss at High Temperature in (Bi1/2Na1/2)TiO3 Ceramic by Controlling A-site Cation Deficiency and Heat Treatment

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Suppression of Dielectric Loss at High Temperature in (Bi1/2Na1/2)TiO3 Ceramic by Controlling A-site Cation Deficiency and Heat Treatment

Ju-hyeon Lee , Geon-ju Lee , Thuy-linh Pham , Jong-sook Lee , Wook Jo
  • : 한국센서학회
  • : 센서학회지 29권1호
  • : 연속간행물
  • : 2020년 01월
  • : 7-13(7pages)

DOI


목차

1. INTRODUCTION
2. EXPERIMENTAL
3. RESULTS AND DISCUSSIONS
4. CONCLUSIONS
ACKNOWLEDGMENT
REFERENCES

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초록 보기


						
Dielectric capacitors are integral components in electronic devices that protect the electric circuit by providing modulated steady voltage. Explosive growth of the electric automobile market has resulted in an increasing demand for dielectric capacitors that can operate at temperatures as high as 400 ℃. To surpass the operation temperature limit of currently available commercial capacitors that operate in temperatures up to 125 ℃, Bi1/2Na1/2TiO3 (BNT), which has a large temperature-insensitive dielectric response with a maximum dielectric permittivity temperature of 300 ℃, was selected. By introducing an intentional A-site cation deficiency and post-heat treatment, we successfully manage to control the dielectric properties of BNT to use it for high-temperature applications. The key feature of this new BNT is remarkable reduction in dielectric loss (0.36 to 0.018) at high temperature (300 ℃). Structural, dielectric, and electrical properties of this newly developed BNT were systematically investigated to understand the underlying mechanism.

UCI(KEPA)

간행물정보

  • : 공학분야  > 전기공학
  • : KCI등재
  • :
  • : 격월
  • : 1225-5475
  • :
  • : 학술지
  • : 연속간행물
  • : 1992-2020
  • : 1766


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1Design of Semiconducting Gas Sensors for Room-Temperature Operation

저자 : Young Geun Song , Gwang Su Kim , Byeong-kwon Ju , Chong-yun Kang

발행기관 : 한국센서학회 간행물 : 센서학회지 29권 1호 발행 연도 : 2020 페이지 : pp. 1-6 (6 pages)

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Gas sensors that operate at room temperature have been extensively studied because of sensor stability, lift time, and power consumption. To design effective room-temperature gas sensors, various nanostructures, such as nanoparticles, nanotubes, nanodomes, or nanofibers, are utilized because of their large-surface-to-volume ratio and unique surface properties. In addition, two-dimensional materials, including MoS2, SnS2, WS2, and MoSe, and ultraviolet-activated methods have been studied to develop ideal room-temperature gas sensors. Herein, a brief overview of state-of-the-art research on room-temperature gas sensors and their sensing properties, including nanostructured materials, two-dimensional materials, the ultraviolet-activated method, and ionic-activated gas sensors, is provided.

2Suppression of Dielectric Loss at High Temperature in (Bi1/2Na1/2)TiO3 Ceramic by Controlling A-site Cation Deficiency and Heat Treatment

저자 : Ju-hyeon Lee , Geon-ju Lee , Thuy-linh Pham , Jong-sook Lee , Wook Jo

발행기관 : 한국센서학회 간행물 : 센서학회지 29권 1호 발행 연도 : 2020 페이지 : pp. 7-13 (7 pages)

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Dielectric capacitors are integral components in electronic devices that protect the electric circuit by providing modulated steady voltage. Explosive growth of the electric automobile market has resulted in an increasing demand for dielectric capacitors that can operate at temperatures as high as 400 ℃. To surpass the operation temperature limit of currently available commercial capacitors that operate in temperatures up to 125 ℃, Bi1/2Na1/2TiO3 (BNT), which has a large temperature-insensitive dielectric response with a maximum dielectric permittivity temperature of 300 ℃, was selected. By introducing an intentional A-site cation deficiency and post-heat treatment, we successfully manage to control the dielectric properties of BNT to use it for high-temperature applications. The key feature of this new BNT is remarkable reduction in dielectric loss (0.36 to 0.018) at high temperature (300 ℃). Structural, dielectric, and electrical properties of this newly developed BNT were systematically investigated to understand the underlying mechanism.

3NO2 Sensing Characteristics of Si MOSFET Gas Sensor Based on Thickness of WO3 Sensing Layer

저자 : Yujeong Jeong , Seongbin Hong , Gyuweon Jung , Dongkyu Jang , Wonjun Shin , Jinwoo Park , Seung-ik Han , Hyungtak Seo , Jong-ho Lee

발행기관 : 한국센서학회 간행물 : 센서학회지 29권 1호 발행 연도 : 2020 페이지 : pp. 14-18 (5 pages)

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This study investigates the nitrogen dioxide (NO2) sensing characteristics of an Si MOSFET gas sensor with a tungsten trioxide (WO3) sensing layer deposited using the sputtering method. The Si MOSFET gas sensor consists of a horizontal floating gate (FG) interdigitated with a control gate (CG). The WO3 sensing layer is deposited on the interdigitated CG-FG of a field effect transistor(FET)- type gas sensor platform. The sensing layer is deposited with different thicknesses of the film ranging from 100 nm to 1 μm by changing the deposition times during the sputtering process. The sensing characteristics of the fabricated gas sensor are measured at different NO2 concentrations and operating temperatures. The response of the gas sensor increases as the NO2 concentration and operating temperature increase. However, the gas sensor has an optimal performance at 180℃ considering both response and recovery speed. The response of the gas sensor increases significantly from 24% to 138% as the thickness of the sensing layer increases from 100 nm to 1 μm. The sputtered WO3 film consists of a dense part and a porous part. As reported in previous work, the area of the porous part of the film increases as the thickness of the film increases. This increased porous part promotes the reaction of the sensing layer with the NO2 gas. Consequently, the response of the gas sensor increases as the thickness of the sputtered WO3 film increases.

4Comparison of Artificial Neural Networks for Low-Power ECG-Classification System

저자 : Amrita Rana , Kyung Ki Kim

발행기관 : 한국센서학회 간행물 : 센서학회지 29권 1호 발행 연도 : 2020 페이지 : pp. 19-26 (8 pages)

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Electrocardiogram (ECG) classification has become an essential task of modern day wearable devices, and can be used to detect cardiovascular diseases. State-of-the-art Artificial Intelligence (AI)-based ECG classifiers have been designed using various artificial neural networks (ANNs). Despite their high accuracy, ANNs require significant computational resources and power. Herein, three different ANNs have been compared: multilayer perceptron (MLP), convolutional neural network (CNN), and spiking neural network (SNN) only for the ECG classification. The ANN model has been developed in Python and Theano, trained on a central processing unit (CPU) platform, and deployed on a PYNQ-Z2 FPGA board to validate the model using a Jupyter notebook. Meanwhile, the hardware accelerator is designed with Overlay, which is a hardware library on PYNQ. For classification, the MIT-BIH dataset obtained from the Physionet library is used. The resulting ANN system can accurately classify four ECG types: normal, atrial premature contraction, left bundle branch block, and premature ventricular contraction. The performance of the ECG classifier models is evaluated based on accuracy and power. Among the three AI algorithms, the SNN requires the lowest power consumption of 0.226 W on-chip, followed by MLP (1.677 W), and CNN (2.266 W). However, the highest accuracy is achieved by the CNN (95%), followed by MLP (76%) and SNN (90%).

5유기 발광 소자 디스플레이를 위한 적외선 램프 소스를 활용한 열 전사 픽셀 패터닝

저자 : 배형우 ( Hyeong Woo Bae ) , 장영찬 ( Youngchan Jang ) , 안명찬 ( Myungchan An ) , 박경태 ( Gyeongtae Park ) , 이동구 ( Donggu Lee )

발행기관 : 한국센서학회 간행물 : 센서학회지 29권 1호 발행 연도 : 2020 페이지 : pp. 27-32 (6 pages)

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This study proposes a pixel-patterning method for organic light-emitting diodes (OLEDs) based on thermal transfer. An infrared lamp was introduced as a heat source, and glass type donor element, which absorbs infrared and generates heat and then transfers the organic layer to the substrate, was designed to selectively sublimate the organic material. A 200 nm-thick layer of molybdenum (Mo) was used as the lightto- heat conversion (LTHC) layer, and a 300 nm-thick layer of patterned silicon dioxide (SiO2), featuring a low heat-transfer coefficient, was formed on top of the LTHC layer to selectively block heat transfer. To prevent the thermal oxidation and diffusion of the LTHC material, a 100 nm-thick layer of silicon nitride (SiNx) was coated on the material. The fabricated donor glass exhibited appropriate temperature-increment property until 249 ℃, which is enough to evaporate the organic materials. The alpha-step thickness profiler and X-ray reflection (XRR) analysis revealed that the thickness of the transferred film decreased with increase in film density. In the patterning test, we achieved a 100 μm-long line and dot pattern with a high transfer accuracy and a mean deviation of ± 4.49 μm. By using the thermal-transfer process, we also fabricated a red phosphorescent device to confirm that the emissive layer was transferred well without the separation of the host and the dopant owing to a difference in their evaporation temperatures. Consequently, its efficiency suffered a minor decline owing to the oxidation of the material caused by the poor vacuum pressure of the process chamber; however, it exhibited an identical color property.

6음향 매질의 추가질량 효과를 고려한 광음향 영상용 초소형 압전 기반 초음파 트랜스듀서의 개발

저자 : 안홍민 ( Hongmin Ahn ) , 문원규 ( Wonkyu Moon )

발행기관 : 한국센서학회 간행물 : 센서학회지 29권 1호 발행 연도 : 2020 페이지 : pp. 33-39 (7 pages)

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Typically, photoacoustic images are obtained in water or gelatin because the impedance of these mediums is similar to that of the human body. However, these acoustic mediums can have an additional mass effect that changes the resonance frequency of the transducer. The acoustic radiation impedance in air is negligible because it is very small compared to that of the transducer. However, the high acoustic impedance of mediums such as the human body and water is quite large compared to that of air, making it difficult to ignore. Specifically, in a case where the equivalent mass is very small, such as with a micro-machined ultrasound transducer, the additional mass effects of the acoustic medium should be considered for an accurate resonance frequency design. In this study, a piezoelectric micro-machined ultrasonic transducer (pMUT) was designed to have a resonance frequency of 10 MHz in the acoustic medium of water, which has similar impedance as the human body. At that time, the resonance frequency of the pMUT in air was calculated at 15.2 MHz. When measuring the center displacement of the manufactured pMUT using a laser vibrometer, the resonance frequencies were measured as 14.3- 15.1 MHz, which is consistent with the finite element method (FEM) simulation results. Finally, photoacoustic images of human hair samples were successfully obtained using the fabricated pMUT.

7플렉서블 기판상에 제작한 다기능 화재센서에 관한 연구

저자 : 서준영 ( Joonyoung Seo ) , 고동완 ( Dongwan Ko ) , 최준석 ( Junseck Choi ) , 노재하 ( Jaeha Noh ) , 정정열 ( Jung-yeul Jung ) , 이문진 ( Moonjin Lee ) , 이상태 ( Sangtae Lee ) , 장지호 ( Jiho Chang )

발행기관 : 한국센서학회 간행물 : 센서학회지 29권 1호 발행 연도 : 2020 페이지 : pp. 40-44 (5 pages)

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An integrated multifunctional sensor, capable of raising an early electric-fire warning, was fabricated. An arc-light, temperature, and humidity sensor was fabricated on a flexible substrate using a printed thin film of indium tin oxide. A polyethylene terephthalate (PET) substrate was used as the flexible substrate. The sensor was fabricated on a PET substrate, and its operating characteristics were tested. The operating performances of the sensor when serving as an arc-light, a temperature, and a humidity sensor were estimated to be 0.6247 Ω/W, 80.6 Ω/K, and -4.08 Ω/RH, respectively. The feasibility of the proposed fire sensor was demonstrated; it costs low and offers multiple functionalities

8PMN-PZT/Ni 자기-전기 복합체에서 단결정 압전 모드에 따른 자기장 감도 특성

저자 : 박소정 ( Sojeong Park ) , Mahesh Peddigari , 류정호 ( Jungho Ryu )

발행기관 : 한국센서학회 간행물 : 센서학회지 29권 1호 발행 연도 : 2020 페이지 : pp. 45-50 (6 pages)

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Magnetoelectric (ME) composites were designed using the PMN-PZT single crystal and Ni foils; the properties and magnetic-field sensitivities of ME composites with different piezoelectric vibration modes (i.e., 31, 32, and 36 modes that depend on the crystal orientation of the single crystal) were compared. In the off-resonance condition, the ME coupling properties of the ME composites with the 32 and 36 piezoelectric vibration modes were better than those of the ME composites with the 31 piezoelectric vibration mode. However, in the resonance condition, the ME coupling properties of the ME composites were almost similar, irrespective of the piezoelectric vibration mode. Additionally, in the off-resonance condition (at 1 kHz), the magnetic-field sensitivity of the ME composites with the 36 piezoelectric vibration mode was up to 2 nT and those of the ME composites with the 31 and 32 piezoelectric vibration modes were up to 5 nT. These magnetic-field sensitivities are similar to those offered by conventional high-sensitivity magnetic-field sensors; the potential of the proposed sensor to replace costly and bulky high-sensitivity magnetic field sensors is significant.

9구조물 안전 모니터링용 파장 스위핑 레이저를 위한 스위핑 자동 선형화

저자 : 이덕규 ( Duk-kyu Lee ) , 엄진섭 ( Jinseob Eom )

발행기관 : 한국센서학회 간행물 : 센서학회지 29권 1호 발행 연도 : 2020 페이지 : pp. 51-58 (8 pages)

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In this study, a novel method for sweeping automatic linearization of wavelength swept laser is proposed. Through the test performed on the implemented laser, the linear sweeping is held up well with a 97% decrease in nonlinearity, and 60 nm sweeping range, 1 kHz sweeping frequency, and 8.8 mW average optical power were obtained. The proposed method uses fiber Bragg grating array, optical-electronic conversion circuit, FPGA embedded module, and a LabVIEW program to generate new compensated wave patterns which were applied to the fiber Fabry-Perot tunable filter. Linear sweeping can reduce the cumbersome and time-consuming recalibration process required for nonlinear sweeping. Additionally, the proposed method provides more accurate measurement results for the structure safety monitoring system.

10TSDC 방법을 이용한 AC 폴링된 PMN-PT 단결정의 디폴링 메커니즘 분석

저자 : 이건주 ( Geon-ju Lee ) , 김황필 ( Hwang-pill Kim ) , 이상구 ( Sang-goo Lee ) , 이호용 ( Ho-yong Lee ) , 조욱 ( Wook Jo )

발행기관 : 한국센서학회 간행물 : 센서학회지 29권 1호 발행 연도 : 2020 페이지 : pp. 59-62 (4 pages)

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Currently, increasing attention is being paid to relaxor-based ferroelectric single crystals in photoacoustic images, especially for highend applications. Among the crystals are (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-100xPT) single crystals located near their morphotropic phase boundary (x = 0.30-0.35) because of their ultrahigh piezoelectric and electromechanical coupling properties. The alternating current poling (ACP) treatment, rather than the conventional direct current poling treatment, has recently been spotlighted due to its effectiveness in enhancing the piezoelectric properties. So far, it has been suggested that the enhanced piezoelectricity originates from either a domain miniaturization to nanodomains or from an electric-field-induced monoclinic symmetry. In this study, we demonstrate by thermally stimulated depolarization current measurements that the effect of ACP is too complex to be explained using a single mechanism and that the proposed electric-field-induced monoclinic symmetry is unlikely to exist.

12
주제별 간행물
간행물명 수록권호

KCI등재

전기전자재료학회논문지(J. Korean Inst. Electr. Electron. Mater. Eng.)
33권 3호 ~ 33권 3호

KCI등재

센서학회지
29권 2호 ~ 29권 2호

E²M-전기 전자와 첨단 소재(구 전기전자재료)
33권 2호 ~ 33권 2호

KCI등재

전기전자재료학회논문지(J. Korean Inst. Electr. Electron. Mater. Eng.)
33권 2호 ~ 33권 2호

KCI등재

센서학회지
29권 1호 ~ 29권 1호

E²M-전기 전자와 첨단 소재(구 전기전자재료)
33권 1호 ~ 33권 1호

KCI등재

전기전자재료학회논문지(J. Korean Inst. Electr. Electron. Mater. Eng.)
33권 1호 ~ 33권 1호

KCI등재

센서학회지
28권 6호 ~ 28권 6호

E²M-전기 전자와 첨단 소재(구 전기전자재료)
32권 6호 ~ 32권 6호

KCI등재

전기전자재료학회논문지(J. Korean Inst. Electr. Electron. Mater. Eng.)
32권 6호 ~ 32권 6호

KCI등재

센서학회지
28권 5호 ~ 28권 5호

E²M-전기 전자와 첨단 소재(구 전기전자재료)
32권 5호 ~ 32권 5호

KCI등재

전기전자재료학회논문지(J. Korean Inst. Electr. Electron. Mater. Eng.)
32권 5호 ~ 32권 5호

KCI등재

센서학회지
28권 4호 ~ 28권 4호

E²M-전기 전자와 첨단 소재(구 전기전자재료)
32권 4호 ~ 32권 4호

KCI등재

전기전자재료학회논문지(J. Korean Inst. Electr. Electron. Mater. Eng.)
32권 4호 ~ 32권 4호

KCI등재

센서학회지
28권 3호 ~ 28권 3호

E²M-전기 전자와 첨단 소재(구 전기전자재료)
32권 3호 ~ 32권 3호

KCI등재

전기전자재료학회논문지(J. Korean Inst. Electr. Electron. Mater. Eng.)
32권 3호 ~ 32권 3호

KCI등재

센서학회지
28권 2호 ~ 28권 2호
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